Online ISSN: 2515-8260

Keywords : Gas Chromatography Mass Spectrum

A Study On Pheromonal Compounds In Sheep (Ovis Aries ) Faeces And Their Behavioural Analysis With Special Reference To Estrus Detection

P. Sangeetha; K. Rameshkumar

European Journal of Molecular & Clinical Medicine, 2020, Volume 7, Issue 8, Pages 4741-4761

Ramnad white is an important indigenous sheep breed in Tamil Nadu and has a
decreasing trend in population, which is alarming as the breed is in critically endangered.
Artificial insemination is needed for frequent breeding and for the conservation of these
animals. Further, the artificial insemination is also difficult in sheep because of few
external estrus signs. In mammals, detection of estrus is one of the most critical
components for successful breeding. The accurate and consistent detection of estrus is also
necessary for successful fertilization and increase the percentage of success in artificial
insemination. Normally, reproduction depends upon the odours released from the female
during the estrus phase. It is well known that mammals emit chemo-signals to the
surroundings via., faeces, saliva, urine and specialized scent glands. Analyzing chemical
signals in the faeces of Ramnad white will aid us to develop estrus detection kit for easy
detection of estrus, so that we can proceed for the improvement of livestock production.
Therefore, the prime objective of the present work is to identify the marker for ovulatory
phase in females and to develop a kit, which would enable to easily identify the
reproductive stage of the animal and allow it for mating and artificial insemination. On the
other hand, chemical signals (pheromones) would be used for provoking sexual behavior
in males. The present work has been designed to analyze the volatiles present in faeces
across the various estrous phases in order to identify estrus markers in female sheep and
a behavioral analysis are also used as supporting information for our present findings. The
samples were collected from sheep in different stages of estrous viz. proestrus, estrus and
postestrus. They were extracted using dichloro methane for GC-MS analysis. The results
showed the presence of nine different compounds with varying molecular weight and
retention time. Among the identified compounds, β-caryophyllene has been exclusively
present only in estrus stage and absent in all other stages. The present study concluded
that the estrus specific compound β-caryophyllene may act as a pheromonal compound
involved in ram communication.